Fractional vortex that carrys the orbital angular momentum is a kind of special vortex with spiral structure.Grating interference,which is made by vortex beams and the plane wave of the angle α with z axis,is used to make fractional vortex through spatial light modulator.Horizontal and vertical superposition grating is used to make the vortex arrays with different topological charge number.Through comparing the superposition of multiple sets of experimental design,the topological charge number vortex beam under the different topological superposition is analyzed.It is found that,as a carrier,the loading information fractional vortex beam is stronger than the integer vortex beam intensity,in which different fractional number,the maximum number of types of the transmission of information lays the theoretical foundation and provides the experimental basis for the reuse of vortex beam in free space communication.